Feeding apparatus for nonrigid sheet

ABSTRACT

Apparatus for separating and delivering single sheets of a nonrigid material from a stack. The sheets in the stack are held in a slightly bent configuration and periodically a corner or peripheral area of the under surface of the bottom piece is exposed and pulled downwardly to allow horizontally movable separating means to move between the stack and the initially partially separated bottom piece to complete its separation, free it from the stack and permit it to drop by gravity.

United States Patent [72] Inventors Ira D. Boynton Lexington; Willard G. Sylvester, Concord, both of, Mass.

[2]] Appl. No. 780,397

[22] Filed Dec. 2, 1968 [45] Patented May 25, 1971 [73] Assignee Apparel Research Foundation, Inc.

Washington, D.C.

[54] FEEDING APPARATUS FOR NONRIGID SHEET 5 Claims, 7 Drawing Figs.

[52] US. Cl 271/33, 271/61 [51] Int. Cl B65h 3/20 [50] Field of Search 271/29, 27, 33, 32,11, 5, 6]

[56] References Cited UNITED STATES PATENTS 679,039 7/1901 Smyth 1,071,928 9/1913 Koemer 3,008,706 11/1961 I-Ieigl et a1 .1:

Primary Examiner-Evon C. Blunk Assistant Examiner-Joseph Wegbreit Attorney-Bessie A. Lepper ABSTRACT: Apparatus for separating and delivering single sheets of a nonrigid material from a stack. The sheets in the stack are held in a slightly bent configuration and periodically a comer or peripheral area of the under surface of the bottom piece is exposed and pulled downwardly to allow horizontally movable separating means to move between the stack and the initially partially separated bottom piece to complete its separation, free it from the stack and permit it to drop by gravity.

Patented May 25, 1971 3,580,564

5 Sheets-Sheet 1 A B C D 2 :0 IO IO IO n u l2 l4 Fig. 1

Ira D. Boynton Willard G. Sylvester INVENTORS AX/ M.

Attorney Patented May 25, 1971 5 Sheets-Sheet 2 N Em HH l lHH HUM lro D. Boynron Willard 6. Sylvester INVENTORS Attorney Pafented May 25, 1971 5 Sheets-Sheet 5 Iro D. Boynron Willard G. Sylvesrer lNvENToRs BY A J Patented May 25, 1971 5 Sheets-Sheet 4 Attorney n W? wwm B wW 0 m l M w E L Y B on. 21 uR l4 OV mm. w m9 M In I W .0 w m U 37% FEEDING APPARATUS FOR NONRIGID SHEET This invention relates to an apparatus for separating and delivering a single piece or sheet of a nonrigid material from a stack of such pieces or sheets.

In many automatic or semiautomatic operations involving limp or nonrigid materials such as sheets, blanks of paper, pieces of fabric, and the like, it is essential to provide means for automatically withdrawing a single piece of the material from a stack and delivering the single sheet directly to a desired point for processing or for transfer to another designated point. As examples of the need for such apparatus we may cite the selection of a piece of cut fabric for transfer to a work point, e.g., sewing machine needle, the selection and transfer of an envelope blank for glue application, and the delivery of single sheets of paper to a printing press.

There are in the prior art many different apparatus to accomplish the selection and delivery of single pieces of nonrigid materials from a stack. Almost without exception these apparatus are designed to take the topmost piece of material from the stack and transport it to a designated point. Such apparatus use suction to pick up the piece, use one or more pressure sensitive adhesive surfaces brought into contact to adhere to the top surface of the topmost piece, use an air stream to separate and float the piece off the stack, or use a combination of these techniques. These apparatus of the prior art are described in such representative US. Pat. Nos. as 3,083,961, 3,168,307 and 3,168,308.

One of the major difficulties encountered in the prior art devices in which a single piece of nonrigid material is to be withdrawn from the top of a stack is the fact that some reliable mechanism must be provided to ensure separation of the topmost sheet and to prevent picking up more than one sheet. This necessity had led to the use of complicated mechanisms for achieving initial separation. In many of the prior art devices which are designed to withdraw the topmost piece it is necessary to stop the feeding mechanism to replenish the supply of sheets on the stack. It is also possible the material to be handled does not lend itself to the prior art processes, e.g., it may be too porous to permit suction pickup, or it may have a surface which does not lend itself to complete suspension from an adhesive surface.

It would therefore be desirable to have an apparatus which does not possess the disadvantages of the prior art devices and which can be integrated into a number of different systems requiring the delivery of successive pieces of nonrigid material. The apparatus of this invention delivers the pieces from the bottom of the stack by a mechanism which provides easy separation of the bottom piece from the stack and delivery by gravity to a point below the stack to a point from which the piece may be transferred. The mechanism for separation and delivery need never be stopped for refilling, for this is done by adding to the top of the stack.

It is thereforea primary object of this invention to provide an improved feeding mechanism for separating and delivering single pieces of nonrigid material from a stack. It is another object of this invention to provide apparatus of the character described which is relatively simple to construct and operate and which can be refilled without stopping the apparatus, thus making it completely continuous. It is another object of this invention to provide apparatus of the character described which is adaptable for use with a wide range of nonrigid materials. Other objects of the invention will in part be obvious and will in part be apparent hereinafter.

The invention accordingly comprises the features of construction, combinations of elements and arrangement of parts which will be exemplified in the construction hereinafter set forth, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings in which:

FIG. I diagrammatically represents the manner in which the apparatus of this invention operates;

FIG. 2 is a top plan view of the apparatus;

FIG. 3 is a side elevational view, partly in cross section, of the apparatus with a portion of the tape-moving mechanism removed;

FIG. 4 is a cross section of the apparatus through two of the belts forming the holding mechanism;

FIG. 5 is a cross section through a belt showing the means by which it is anchored;

FIG. 6 is a cross section through the apparatus showing the tape-moving mechanism; and

FIG. 7 is a cross section of the tape-moving mechanism taken along line 7-7 of FIG. 6.

In the apparatus of this invention the piece of limp or nonrigid material is taken from the bottom of a stack, thus permitting the stack to be replenished continuously without having to stop the mechanism. This is accomplished through the operation of the apparatus as illustrated in the four steps of FIG. 1. A stack 10 of limp blanks or pieces is so arranged and held to impart to them a slight bent configuration thus giving each of the pieces in the stack a degree of rigidity. As will be explained later in conjunction with the detailed description of the apparatus of this invention, the stack is so held that a small comer or peripheral area of the bottom piece is periodically exposed. On the under surface of this exposed piece, a vertically movable, temporary adhering member 11 is contacted and moved in such a way as to bend down the corner 12 of the bottom piece as illustrated in step C. A horizontally movable separating member 13 is then advanced between the bottom piece and the next lowest piece in order to separate it from the stack and to detach this bottom piece 14 so that it may fall free by gravity onto any suitable collecting member. Although in the apparatus illustrated the vertically movable, temporary adhering member 11 is shown as a piece of pressure-sensitive adhesive tape, it may, of course, take other forms such as an area of slightly bent pins (e.g., card cloth) with or without a suction mechanism. Likewise, the horizontally movable separating member which detaches the bottom piece from the stack may be, in addition to the roller illustrated, a jet of air or any other suitable means for separating this bottom piece.

In the apparatus of this invention as illustrated in FIGS. 2 through 7, the stack of limp pieces is held stationary while a series of belts move under it, thus providing the means for exposing a corner of the bottom piece and also for permitting the horizontal movable separating member to come between the bottom piece and the second lowermost piece of the material in the stack. The manner in-which the stack 10 is held and the belts move is illustrated in FIGS. 2 and 3, and reference should be had to both of these drawings in the following description.

Four belts, 21, 22, 23, and 24, are provided as the holding means and between these belts there is defined a gap 25 which permits the under surface of the bottom piece of the material to be exposed. As will be apparent in FIG. 4, the pairs of belts, namely 21 and 22, and 23 and 24, are positioned so as to define a V-shaped holding member. The pieces of the stacked material when placed in this holding member are, therefore, slightly bent to conform to the sides of the belts and are thus given a slight degree of rigidity. The top surfaces of the belts themselves do not move but their supports do. This means that the stack is held in one plane, but that a separating roller and the belts are free to roll under the stack. In order to achieve this, there is provided a belt frame 26 to which are affixed belt rollers. The frame 26 moves in a horizontal plane and relative to the main frame in a series of upper guide rollers 27 and lower guide rollers 27a. It is, however, primarily supported by the belts which are affixed to anchoring members bolted to the main frame. Taking belts 21 and 22 as exemplary of the way in which they are mounted, it will be seen in FIG. 2 that there are provided belt rollers 28 and 29 associated with the left-hand ends of belts 21 and 22. These belt rollers are joined by a center horizontal joining member 30. In like manner the righthand sides of belts 21 and 22 are supported by belt rollers 31 and 32 joined by a horizontal center piece 33. The belts are anchored by means of anchoring pieces 35 and 36 which also are joined by a central horizontal member 37. This may be seen more clearly in FIGS. 4 and 5 which show in detail the manner in which belt 22 is affixed to the frame. Belt roller 32 is mounted between frame 26 and center belt-holding member 37, and the belt 22 is attached to the belt-anchoring piece 36 by means of two pressure plates 38 (one on each side) and bolts 39 which pass through the entire assembly and grip the belt ends to anchor them to the belt-anchoring member 36. In like manner all four belts are anchored to their respective anchoring means.

The belt-anchoring members 35 and 36 are 'in turn affixed to outer frame members 40 and 41 which are in themselves affixed to vertical support members 42 and 43 which form a portion of the main frame of the apparatus. The horizontal movable separating member 13 in the apparatus of this invention takes the form of two rollers 45 and 46 which are positioned to be aligned at the same as belts 21 and 22. These rollers are joined by a central horizontal roller 47 and are mounted for rotation through shafts 48 and 49 into the frame 26. As the frame moves back and forth rollers 45 and 46 move with it and they are rotated by contact with belts 21 and 22. ln rolling, rollers 45 and 46 pull down on the top surface of the bottom piece which has been partially separated from the stack by action of adhesive tape. Continued forward movement of the rollers 45 and 46 completes the separation.

Belts 23 and 24 have associated with them belt-holding members 51 and 53 joined by a central member 52in the same manner in which belts 21 and 22 are mounted and anchored to frame 26. The arrangement in which this is done is identical to that shown for belt 22 in FIGS. 4 and 5. In like manner the belt-anchoring members 51 and 53 are attached to vertical supporting members 55 and 56 which correspond to members 42 and 43 and which serve as the other portion of the vertical frame for the apparatus.

Within the outer frame (which is defined by members 40, 41, 35, 37, 36, 51, 52 and 53) are four horizontal supporting frames 60, 61, 62 and 63. These are designed to support four angled positioning members 64, 65, 66 and 67 through horizontal support pieces 68, 69, 70 and 71, respectively. It will, of course, be apparent to any one skilled in the art that these positioning pieces 64-67 may take any location and any shape depending upon the configuration of the stack of cloth or limp pieces which are to be processed.

Movement of the frame and of the belt surfaces is achieved through the use of a frame-moving means 75 which in the embodiment shown in FIGS. 2 and 3 comprises a fluid-driven cylinder 76 mounted in frames 77 and 78 and having associated with each end a fluid supply means 79 and 80. This frame driving system may, of course, be constructed in accordance with any suitable known manner and may comprise any driving systems which can be controlled and timed for integration with the tape driving system to be described. As will be seen from FlG. 3, the cylinder is connected to the frame 26 through a pair of pulleys 85 and 86, a cable 07, a clip 80, and a frame 89 which joins the clip 88 and the main movable frame 26.

The means for pulling the exposed corner or peripheral area of the bottom limp piece in the embodiment of the apparatus of this invention shown in the drawings comprises a mechanism whereby a pressure-sensitive adhesive tape is moved up to contact a small area of the under surface of the bottom piece, and through shearing action pulls down a comer or small peripheral area so that the horizontal moving member may interpose itself between the bottom piece and the next piece in the stack. In order to use a pressure-sensitive adhesive tape in this manner it is, of course, necessary to be able to advance it in small discrete steps and at the same time move the tape up and down so that it may periodically make contact with the under surface of the bottom piece in the stack. A portion of the mechanism to accomplish this is shown in FIG. 3 and is illustrated in detail in FIGS. 6 and 7. Reference should therefore be had to these three drawings in connection with the following description.

As will be seen in FIGS. 6 and 7, the pressure-sensitive adhesive tape is held in tension between a tape supply roll 101 and a tape takeup roll 102. These supply and takeup rolls are mounted on an oscillating shaft 105 which in turn is mounted in two support systems 106 and 107 to be described in detail below.

The tape supply roll 101 is affixed to the shaft 105 through an arm 110 which is attached to the roll 111 from which the tape is pulled off. By means of a wing nut 112, a spring 113, and a pressure plate 114, it is possible to apply a controlled amount of drag to the supply tape roll which is mounted on the shaft 115 and around which roll 111 rotates.

In a somewhat similar fashion the takeup roll 102 is mounted to an arm which in turn is used to support a system of one-way clutches on the housing 121 of which the used tape is wound. A first one-way clutch 123 is affixed through key 124 to shaft 122. The one-way clutch 123 is constructed in any suitable known form and is commercially available. Its purpose is to insure that the takeup roll rotates in only one direction, namely that shown by the arrow in FIG. 6. In addition to one-way clutch 123 there is provided another one-way clutch mechanism which comprises arm 125 which extends upwardly around shaft 122, spring 126 anchored to housing extension 127 and a second one-way clutch 120. Arm 125 is designed to oscillate on shaft 122 between adjustable stops and is spring loaded through its attachment to spring 126. As main shaft 105 oscillates the spring 126 applies a force to oscillate arm 125 to rotate about shaft 122. Arm 125 is connected to the inner race of one-way clutch 128. The outer race of clutch 128 drives the roll 102. Thus the oscillation of arm 125 drives roll 102 to wind it up over a given distance to take up a predetermined amount of tape for each cycle.

In oscillating back and forth the main shaft 105 and the arms 110 and 120 also oscillate the supply roll 101 and the takeup roll 102 through the same angle. In order to make the pressure-sensitive adhesive tape 100 available for contact with the under surface of the bottom limp piece, it is necessary to thread it so that it passes with the adhesive side exposed over an anvil-shaped member 130 which is affixed to the central portion of the shaft 105. ln doing this it is preferable to pass the tape 100 through appropriately designed passageways 131 and 132 out in the shaft.

The oscillating motion of the shaft and hence of the tape and the tape supply, and takeup rolls is achieved through the use of a rack and rack-driving means as shown in FIG. 3. Rack is affixed to a cylinder 146 which is driven back and forth in a cylinder housing 147 by any suitable known mechanism, e.g., a fluid-actuated cylinder. The driving cylinder mechanism is attached to the vertical frame 43 through means of an arm 148. The rack is supported on a rotating pin 149 mounted in a frame 150.

Taking first the driving means 106 which is associated with the takeup roll, it will be seen in FIG. 6 that it is comprised of an outer bearing and an inner bearing 156 (see also FIG. 3). Associated with these bearings is an eccentric 160 which has fixed to it a gear 161 arranged to mesh with the teeth of I rack 145, thus imparting to the eccentric and to the bearings an oscillating motion as the rack 145 is moved back and forth by the introduction and discharge of a driving fluid into cylinder 147.

The oscillating system 107 is connected to the oscillating system 106 by means of a shaft 165 which provides a mechanical connection to the two driving systems in addition to shaft 105. The arrangement of driving mechanism 107 is somewhat similar to that of 106, except that it does not have a rack associated therewith. However, it does have means for controlling the motion of the tape, i.e., forcing the tape to move straight upwardly when it is time for it to make connection with the under surface of the bottom piece of the stack. This is accomplished through the use of a mechanism attached to the shaft which comprises a cam follower support and a cam follower 176 in the form of a finger. As the shaft is rotated the cam follower [76 moves with the shaft (as will be apparent from the drawing in FlG. 3) and when it has reached its uppermost position it is forced to move upwardly by the cam surface K77 which, as will be seen in FIG. 3, is so positioned to cause the cam follower to ride directly upwardlyand force the tape into contact for a desirable period of time with the under surface of the bottom limp piece. This, in effect, means that as the tape swings up and around it will contact the under surface of the bottom piece and attaches itself thereto. As the tape is rotated back, it effects a shearing back motion to roll the comer of the bottom limp piece down through the gap 25, thus defining a space between the pulled-down corner of the bottom limp piece and the stack to permit the horizontal movable separating member, i.e., the roller 45 (see FIG. 2) to pass between the bottom piece and the stack.

The operation of this apparatus may be described with reference to FIGS. 2, 3 and 6. A supply of nonrigid or limp pieces is placed as a stack within the positioning members 64-67 on the belts 23 and 24. The V-configuration of these belts gives the stack a corresponding V-configuration, thus imparting some slight rigidity to each piece in the stack. Assume to begin that the belt frame 26 is shifted to the position shown in FIG. 3. This then provides for a corner of the bottom piece of the stack to hang over the left-hand ends of belts 23 and 24 into gap 25. Because of the stiffness imparted to the pieces, these corners remain essentially horizontal as shown in FIG. 3. At this point the rack 145 is driven forward, i.e., towards the right to turn shaft 105 counterclockwise, and to bring anvil 130 (FIG. 6) up to its upright position. Cam follower 176 is at the same time brought into contact with cam 177, the vertical surface of which ensures that the exposed adhesive surface of the tape makes sufficient contact with the under surface of the horizontally positioned corner of the bottom piece. Then the rack 145 is moved back to turn the shaft 105 clockwise, pull the tape down with a shearing action and pull the comer of the bottom piece down.

After the comer of the bottom piece is bent down thus completing a partial initial separation and the tape has begun to swing out of the way, the driving means associated with the belt frame 26 is actuated to move the cable and hence the frame 26 is a forward motion, i.e., to the right in FIG. 3. Because the belts 21, 22, 23 and 24 are anchored as described to the anchoring frames (formed of members 35, 36 and 37 for belts 21 and 22 and of members 51, 52 and 53 for belts 23 and 24), the actual surfaces of the belts do not move but the belts in effect change their positions with respect to the fixed position of the stack. Thus the two sets of belts 21 and 22 and 23 and 24 in effect can be shifted back and forth under the stack. Therefore, as frame 26 is moved to the right, belts 23 and 24 in effect move away from under the stack while belts 21 and 22 in effect begin to move under the stack. The final separating and discharging means formed of roller members 45, 46 and 47 are rotated by contact with belts 21 and 22 and as the frame shifts to the right these roller members come between the turned down comer 12 (FIG. 6) of the bottom piece and the remainder of the stack. With continued forward motion the roller members 45, 46 and 47 finally peel the bottom piece off and allow it to drop freely. The frame is then returned by backward action of cable 87 to the position shown in FIG. 3. As this is being accomplished the shaft 105 is being rotated again, as previously described, to bring the tape into position when the comer of the stack is again over gap 25 and the cycle begins again.

In operation of the apparatus it is of course necessary to control the driving means associated with the moving belt frame 26 (e.g., fluid-driven cylinder 76) as well as the driving means associated with the oscillation of the tape anvil 130 on shaft 105 (e.g., the fluid-driven cylinder 146) and to time them so that they operate in proper sequence. When anvil 130 is rotated so that the tape surface makes contact with the under surface of the bottom piece of the stack the belt frame 26 must be in a position to locate gap 25 over the anvil. This serves to expose a corner or peripheral area of the under surface of the bottom piece to the tape. Then as the tape is rotated down, back and out of the way, the belt frame 26 is driven forward (i.e., to the right in FIG. 3) to roll gap 25 and the separator rolls 45, 46, 47 across the bottom of the stack to complete the separation of the bottom piece from the stack.

There are a number of known systems which may be used to effect such control and timing of these driving means. For example fluid amplifier devices operating with pneumatic sensing devices may be used to control the fiow of a pneumatic fluid within the cylinders shown. Likewise timed limit switches can be used to actuate suitable driving means capable of effecting back and forth motions of the frame 26 and rack 145.

It will thus be seen that the objects set forth above, among those made apparent from the preceding description, are efficiently attained and, since certain changes may be made in the above construction without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

We claim:

1. An apparatus for separating and delivering single pieces ofa nonrigid material from a stack, comprising in combination a. means for holding a stack of pieces of nonrigid material in a fixed position and in a slightly bent configuration thereby to impart some rigidity to the stacked pieces, said means being adapted periodically to expose a small peripheral area of the under side of the bottom piece in said stack and comprising two pairs of belts, the belts making up each pair being maintained in an inclined position to form a broad V, each of said belts being anchored by its two ends to a member fixed to the main frame of said apparatus and being stretched between roller members affixed to a frame capable of being moved in a horizontal plane;

b. initial separating means adapted to contact said exposed peripheral area of the under side of said bottom piece and in its movement to initially separate a portion of said bottom piece from said stack;

c. piece discharging means adapted to complete the separation of said bottom piece from said stack while said stack remains in said fixed position thereby to permit said bottom piece to fall by gravity to a position below said stack; and

d. means for driving said initial separating means and said piece discharging means in a predetermined sequence.

2. An apparatus in accordance with claim 1 wherein said piece discharging means comprises roller means in contact with the forward edges of one pair of said belts.

3. An apparatus in accordance with claim 1 wherein said initial separating means comprises a pressure-sensitive adhesive surface and means to periodically bring it into contact with said under side of said bottom piece.

4. An apparatus for separating and delivering single pieces of a nonrigid material from a stack, comprising in combination a. a main frame structure;

b. two pairs of belts, the belts making up each pair being maintained in an inclined position to form a broad V and being anchored by their ends to anchoring members affixed to said main frame;

c. a movable belt frame on which said belts are mounted through belt rollers in a manner to define a gap between said pairs of belts;

d. positioning means defining the fixed location of a stack of said single pieces adapted to permit said stack to be supported by the surfaces of said belts and to permit a small peripheral area of the under side of the bottom piece of said stack to be periodically exposed within said gap;

e. initial separating means adapted to contact said exposed peripheral area of the under side of said bottom piece and in its movement to initially separate a portion of said bottom piece from said stack;

of a nonrigid material from a stack, comprising in combination a. a main frame structure;

b. two pairs of belts, the belts making up each pair being maintained in an inclined position to form a broad V and being anchored by their ends to anchoring members affixed to said main frame;

c. a movable belt frame on which said belts are mounted through belt rollers in a manner to define between a gap between said pairs of belts;

d. positioning means defining the fixed location of a stack of said single pieces adapted to permit said stack to be supported by the surfaces of said belts and to permit a small peripheral area of the under side of the bottom piece of said stack to be periodically exposed within said gap;

e. initial separating means, adapted to contact said exposed peripheral area of the under side of said bottom piece, comprising a pressure-sensitive adhesive surface and means to periodically bring it into contact with said under side of said bottom piece;

f. piece discharging means adapted to complete the separation of said bottom piece from said stack and comprising roller means in contact with the forward edges of one pair of said belts; and

g. means for driving said movable belt frame and said initial separating means in a predetermined sequence. 

1. An apparatus for separating and delivering single pieces of a nonrigid material from a stack, comprising in combination a. means for holding a stack of pieces of nonrigid material in a fixed position and in a slightly bent configuration thereby to impart some rigidity to the stacked pieces, said means being adapted periodIcally to expose a small peripheral area of the under side of the bottom piece in said stack and comprising two pairs of belts, the belts making up each pair being maintained in an inclined position to form a broad V, each of said belts being anchored by its two ends to a member fixed to the main frame of said apparatus and being stretched between roller members affixed to a frame capable of being moved in a horizontal plane; b. initial separating means adapted to contact said exposed peripheral area of the under side of said bottom piece and in its movement to initially separate a portion of said bottom piece from said stack; c. piece discharging means adapted to complete the separation of said bottom piece from said stack while said stack remains in said fixed position thereby to permit said bottom piece to fall by gravity to a position below said stack; and d. means for driving said initial separating means and said piece discharging means in a predetermined sequence.
 2. An apparatus in accordance with claim 1 wherein said piece discharging means comprises roller means in contact with the forward edges of one pair of said belts.
 3. An apparatus in accordance with claim 1 wherein said initial separating means comprises a pressure-sensitive adhesive surface and means to periodically bring it into contact with said under side of said bottom piece.
 4. An apparatus for separating and delivering single pieces of a nonrigid material from a stack, comprising in combination a. a main frame structure; b. two pairs of belts, the belts making up each pair being maintained in an inclined position to form a broad V and being anchored by their ends to anchoring members affixed to said main frame; c. a movable belt frame on which said belts are mounted through belt rollers in a manner to define a gap between said pairs of belts; d. positioning means defining the fixed location of a stack of said single pieces adapted to permit said stack to be supported by the surfaces of said belts and to permit a small peripheral area of the under side of the bottom piece of said stack to be periodically exposed within said gap; e. initial separating means adapted to contact said exposed peripheral area of the under side of said bottom piece and in its movement to initially separate a portion of said bottom piece from said stack; f. piece discharging means adapted to complete the separation of said bottom piece from said stack while said stack remains in said fixed position thereby to permit said bottom piece to fall by gravity to a position below said stack; and g. means for driving said initial separating means and said movable belt frame in a predetermined sequence.
 5. An apparatus for separating and delivering single pieces of a nonrigid material from a stack, comprising in combination a. a main frame structure; b. two pairs of belts, the belts making up each pair being maintained in an inclined position to form a broad V and being anchored by their ends to anchoring members affixed to said main frame; c. a movable belt frame on which said belts are mounted through belt rollers in a manner to define between a gap between said pairs of belts; d. positioning means defining the fixed location of a stack of said single pieces adapted to permit said stack to be supported by the surfaces of said belts and to permit a small peripheral area of the under side of the bottom piece of said stack to be periodically exposed within said gap; e. initial separating means, adapted to contact said exposed peripheral area of the under side of said bottom piece, comprising a pressure-sensitive adhesive surface and means to periodically bring it into contact with said under side of said bottom piece; f. piece discharging means adapted to complete the separation of said bottom piece from said stack and comprising roller means in contact with the forward edges of one pair of said belts; and g. means for driving said movable belt frame and said initial separating means in a predetermined sequence. 